What are the performance indexes of meltblown& spunbonded nonwoven fabric?

1.Uniformity

The uniformity is expressed by the discrete coefficient CV value of quantitative value, which reflects the uneven distribution of fiber mesh (thick and thin) of the product. The greater the CV value, the worse the quality of the product. Generally, the larger the quantitative value of the product, the smaller the CV value. The CV value is in “%”. Quantitative, which is defined as the weight (quality) of product per unit area, and the legal unit of measurement in China is g / m2 or g / m2

2.Powerful

Strength refers to the maximum force required to break the product during the strength (tensile) test, and the unit is N. The greater the strength, the better the quality of the product. The strength is not only related to the quantitative size of the product (the greater the quantitative, the greater the strength), but also related to the stress direction of the product.

The direction of the product is generally divided into two types: the running direction of the production line (referred to as MD) and the horizontal direction (the direction perpendicular to the running direction of the nonwoven production line, referred to as CD). With the different mesh laying methods used in the production line, the anisotropic phenomenon exists in general products. For example, the MD direction strength of products with longitudinal mesh laying will be larger, and the MD strength of some production lines can be twice or even more than that of CD. The strength of the same product is also different in different directions. In practical application, it is hoped that the longitudinal and transverse strength are close to each other, so that the product is isotropic.

3.Elongation at break

Elongation at break refers to the ratio of the elongation part of the product to the original length of the sample during the tensile test. The unit of elongation at break is "%". When the product quality is good and the fiber is fully drawn, the elongation at break is less than 100%; The elongation at break of melt blown cloth is small, generally less than 50%.

Because the breaking strength of the product is different in two directions, the breaking elongation of MD and CD is also different. In most application fields, the smaller the elongation at break is, the better, and the elongation at break in different directions should be as close as possible.

4.Permeability

Permeability is an index reflecting the hydrophilic ability of the product in the spinning and melting sanitary materials, which indicates the ability of the liquid to pass through the product (fast and slow). The permeability can be divided into one-time permeability and multiple permeability. The shorter the time, the better.

5.Hydrostatic pressure (HSH)

In sanitary materials, hydrostatic pressure is an index reflecting the barrier capacity of products, which indicates the ability of products to bear a certain pressure (hydrostatic pressure) liquid. The unit of measurement is "mm water column" or "cm water column", sometimes expressed by PA (PA), the greater the value, the better. The hydrostatic pressure of 15 g / m2 sanitary materials should be about 150 mm water column. For the same type of product, the greater the ration, the higher the hydrostatic pressure.

6.Air permeability

Air permeability is an index when nonwovens are used as gas filtration materials. It reflects the gas permeability of both sides of the product under the condition of specified pressure difference. It is expressed by the gas permeability per unit time. The higher the air permeability is, the easier the gas passes through the nonwoven fabric.

7.Antistatic

Antistatic property is the index of the dissipative static power of spinning and melting products. The better the antistatic performance, the less electrostatic can accumulate on the product, the higher the safety of the product. The antistatic performance is usually expressed by surface volume resistance, in ohm(Ω)。 The smaller the surface resistance, the better the antistatic performance. Sometimes, the static half-life (s), or surface charge amount are used to express the antistatic performance of the product. The shorter the half-life or the less surface charge, the better the antistatic performance.